var EleResize = {
    _handleResize: function (e) {
      var ele = e.target || e.srcElement
      var trigger = ele.__resizeTrigger__
      if (trigger) {
        var handlers = trigger.__z_resizeListeners
        if (handlers) {
          var size = handlers.length
          for (var i = 0; i < size; i++) {
            var h = handlers[i]
            var handler = h.handler
            var context = h.context
            handler.apply(context, [e])
          }
        }
      }
    },
    _removeHandler: function (ele, handler, context) {
      var handlers = ele.__z_resizeListeners
      if (handlers) {
        var size = handlers.length
        for (var i = 0; i < size; i++) {
          var h = handlers[i]
          if (h.handler === handler && h.context === context) {
            handlers.splice(i, 1)
            return
          }
        }
      }
    },
    _createResizeTrigger: function (ele) {
      var obj = document.createElement('object')
      obj.setAttribute('style',
        'display: block; position: absolute; top: 0; left: 0; height: 100%; width: 100%; overflow: hidden;opacity: 0; pointer-events: none; z-index: -1;')
      obj.onload = EleResize._handleObjectLoad
      obj.type = 'text/html'
      ele.appendChild(obj)
      obj.data = 'about:blank'
      return obj
    },
    _handleObjectLoad: function (evt) {
      this.contentDocument.defaultView.__resizeTrigger__ = this.__resizeElement__
      this.contentDocument.defaultView.addEventListener('resize', EleResize._handleResize)
    }
  }
  if (document.attachEvent) { // ie9-10
    EleResize.on = function (ele, handler, context) {
      var handlers = ele.__z_resizeListeners
      if (!handlers) {
        handlers = []
        ele.__z_resizeListeners = handlers
        ele.__resizeTrigger__ = ele
        ele.attachEvent('onresize', EleResize._handleResize)
      }
      handlers.push({
        handler: handler,
        context: context
      })
    }
    EleResize.off = function (ele, handler, context) {
      var handlers = ele.__z_resizeListeners
      if (handlers) {
        EleResize._removeHandler(ele, handler, context)
        if (handlers.length === 0) {
          ele.detachEvent('onresize', EleResize._handleResize)
          delete ele.__z_resizeListeners
        }
      }
    }
  } else {
    EleResize.on = function (ele, handler, context) {
      var handlers = ele.__z_resizeListeners
      if (!handlers) {
        handlers = []
        ele.__z_resizeListeners = handlers
  
        if (getComputedStyle(ele, null).position === 'static') {
          ele.style.position = 'relative'
        }
        var obj = EleResize._createResizeTrigger(ele)
        ele.__resizeTrigger__ = obj
        obj.__resizeElement__ = ele
      }
      handlers.push({
        handler: handler,
        context: context
      })
    }
    EleResize.off = function (ele, handler, context) {
      var handlers = ele.__z_resizeListeners
      if (handlers) {
        EleResize._removeHandler(ele, handler, context)
        if (handlers.length === 0) {
          var trigger = ele.__resizeTrigger__
          if (trigger) {
            trigger.contentDocument.defaultView.removeEventListener('resize', EleResize._handleResize)
            ele.removeChild(trigger)
            delete ele.__resizeTrigger__
          }
          delete ele.__z_resizeListeners
        }
      }
    }
  }
  export {EleResize}
  
  